The present invention relates to novel adhesives and, more particularly, to novel adhesives which can be coated onto an aluminum or other metal foil backing material to provide so-called foil tapes which meet the very severe Underwriter Laboratories, Inc. (UL) 181A requirements and specifications for use with rigid fiberglass air ducts.
Foil tapes, e.g. pressure-sensitive or heat-bonded aluminum tapes are of course in the art. It is also heretofore known to employ foil tapes for closure systems for use with factory-made air ducts and connectors. However, recently UL has imposed very severe standards for their usage, both as to adhesive qualities and to flame retardation.
Acrylic adhesives are known in the art which are capable of meeting these severe standards. However, the known acrylic formulations for this purpose suffer from two major deficiencies, namely cost-effectiveness and performance.
With respect to the former, there is a great need by adhesive and adhesive tape manufacturers for an appreciably less expensive foil tape meeting the UL 181A requirements.
As to the latter, acrylics as a class do not always exhibit entirely satisfactory shear performance over long term and at high temperatures. Consequently, there is also a great need for a foil tape having superior performance under these conditions.
The task of the present invention may accordingly be described as three-fold: (1) to manufacture a more cost-effective foil tape (2) which will meet the UL 181A requirements to be described in detail hereinafter (3) and which will provide markedly improved performance over long term and at higher temperature.
The UL 181A specifications detailed hereinafter for pressure-sensitive aluminum tapes for use with rigid fiberglass air ducts require an aluminum or aluminum alloy foil covered on one side with adhesive. The adhesive surface shall be protected by a release paper intended to be removed at the time of tape installation.